"Combo-based" combat system

Hello there. So I was brainstorming some ideas for the next game I will be making, and I had some ideas that were inspired by playing Final Fantasy 14.

The game is a zombie apocalypse style "survival horror" turn-based RPG game (although it won't really be too much on the horror side, more-so a game like Parasite Eve for those who are familiar).

The game will feature 3 playable characters, each with their own strengths and weaknesses.

Electrician will be the states master class (poisons, bleeds, stuns, etc).

Cultist Agent (name pending) will be the damager/tank class.

Schoolgirl will be the healer and support type class.

The way the combos work is when you use the combo starting move, it allows you to use the next move in the combo on the following turn. Some combos are only 2 tiers long, but some are longer. All names are pending, since this is very early alpha stages in development. All moves require MP so each class will have a combo that also helps them replenish mana.

Precise Strike (Basic Damage Ability) ---> Defense Break (Reduce Enemy defense by x% for a x turns) ---> Power Break (Reduce Enemy attack by x% for a x turns)

                                                          or ---> Power Syphon (Deals damage and Restores x mana)

                                                          or ---> Savage Strike (Damage Ability, stronger than the Precise Strike) ---> Brutal Bash  (Damage Ability, stronger than Savage Strike)

                                                                                                                                                                         or ---> Sweeping Blow (Hits all enemies and chance to stun them for 1 turn)

Taunt (Increases threat by x%) ---> Flash (Reduces enemy hit by x% for x turns)

                                              or ---> Barricade (Increases threat by x% more, and increases self-defense by x% for x turns) ---> Protega (Increases party defense by x% for x turns)

To add to this, I'm using using "Galv's Timed Button Attack" script in which you have to press a button at the right moment (think Legend of Dragoon gameplay), and if you do it successfully, your damage for that attack is increased by 25% (and some skills will add states, such as bleeds, poisons, confusion, etc if you do it correctly). There is no consequence for not getting it right, as to not punish the player. In the same sense, when an enemy attacks you, you get a timed-button pop-up as well, and if you do it correctly you effectively reduce the incoming damage by up to 30%.

What do you guys think? Would this be something you would find interesting?

Here's a little demo with my idea in action:

http://www.mediafire.com/download/n27nwgx2btk8gly/The_Plague.exe

I like the concept of zombie apocalypse being presented as an RPG with turn-based battles (usually they're shooters, survival horror, or something of that sort). I am not sure I am understanding the combo mechanics fully. By combo, do you mean a move that unlocks once you've executed the first one in the chain, right? (when you said combo at first, I thought it's 2 characters doing a combo move together). I'd say sure why not. So long as the chains are not too limiting and that every battle does not end up requiring the same strategy, then this could turn out really well. 

"do you mean a move that unlocks once you've executed the first one in the chain" <---This. You would have access to all the abilities, but they can't be used until the 1st part of the combo is used.

I'm still on the fence of making it 1 attack per turn, or going with the combo-input script that yanfly has, where you queue your attacks and unleash them all in one turn if you have the resources to do so.

As for the combo side of things, was thinking of making the Electrician and the Cultist Agent play off each other's attacks. For example, if monster has "x" state caused by the Electrician, then "y" attack from the cultist does more damage or adds "z" state too. 

I think having to pull out the entire combo in the same turn might get a bit old. It could make battles a bit chaotic and even repetitive, because the player will just be doing that every turn, and the rest of the time probably just spamming attack (I might be wrong though). I just think doing one part of the combo per turn will be more strategic, especially if with each step you open up 2 or 3 skills rather than just 1.

And that second idea is good too and really opens up a lot to strategy. I've got stuff like that in my current project in fact. E.g. an attack that does more damage to a stunned enemy (and another party member having an attack that can stun enemies), or an attack that does more damage when the character doing it is poisoned, and so on.

There would definitely be an issue of repetitiveness going on. If you're trying to make something similar to Legend of Dragoon's addition system, please make sure it's 10x better, because it was one of the things that people disliked most about that game.

The whole "playing off each other's attacks" sounds much better though.

I find it funny that so many people disliked that about Legend of Dragoon, when I personally found it to be one of my favorite parts about the game, repetitive or not. In any rpg-style game though, you're going to run into some sort of repetitiveness, it's just a matter of making somewhat fun and not so bland that is key. I'm definitely open to feedback on how to keep it from getting repetitive though, so for those who do try out the demo, please, do share any ideas you may have!

I think your idea is awesome, i will share you also an idea a I got for my RPG, its also a combo system but players will press a combination of keystrokes, like on the numeric keypad Press 4 for swing left then Press 5 to pierce then Press 6 to swing right, this is done with a weopon in hand.

By tracking the combo successful hit, this will gain the user a Combo Experience which let the character increase its damage when using the same combo.

I still didn't think of a game concept but I will try to think more ideas.

What do you think about this?